Weather conditions are being blamed for creating a situation that led to the death of thousands of bait fish in Belmar's Shark River.

Fish kill in Belmar
Fish kill in Belmar (S.A.N.D.)

The New Jersey Department of Environmental Protection believes oxygen depletion, caused by the weekend's heavy rains and sudden increase in temperature, led to thousands of menhaden -- a species of bait fish also known as moss bunker fish -- to wash up Monday morning.

The DEP, which is continuing the investigation, says the species is particularly sensitive to oxygen depletion conditions and can be susceptible to these natural fish kills when the right combination of factors is present.

"We had heavy rains over the weekend which churned up the waters and likely brought nutrients to the surface of the water," said DEP spokesman Larry Ragonese. "Summer occurred all of a sudden this weekend and the hot weather 'cooks' the nutrients. The algae that's formed love the oxygen, and start eating it."

Ragonese said the problem primarily affected the menhaden, not other species that are more tolerant to the oxygen fluctuations.

"We found a handful of flounder, a couple of puffers, a couple of wheat fish, but you're talking virtually 99 percent of the bait fish," Ragonese said.

While the oxygen depletion is the primary and most likely theory the DEP has, the agency is investigating the possibility of other causes, such as chemical contamination, illnesses from the fish, or already dead menhaden being dumped by commercial fishing operations.
Ragonese said the fish kill poses no harm to humans and will largely have no effect on the ecosystem, noting the dead fish were almost instantly being eaten by other predators.

"We had a fish kill down in the Delaware Bay a couple of years ago and I believe we had two or three million menhaden that died," he said.